This seems a really odd question to ask, but when talking to, say, Halsin in the camp (I'm in Act II), I don't get an option to make him join my party. So how does that work? Or is it supposed to not work?
Halsin will be at your camp but only join you a bit later when certain quests involving him are finished.
I was surprised to see the beefiest bodybuilder guy in the game has 10 Strength. With all the attention to detail, it's odd such a simple thing like character stats are so far off from how the characters are presented. Not as bad as an "archdruid" mechanically being level 5-7 though. There's a dissonance and wish the game mechanics and storytelling would support each other rather than what seems like completely ignoring each other. Level 7 PC's acting like they are much more powerful isn't cool. That and the fact that they come into your party with level 1 starting equipment makes me not want to ever travel with them.